Embodiments of the invention relate to a mobile environment-controlled unit, such as an over-the-road compartment trailer, having an environmental-control system, such as a refrigeration unit, powered by an alternator and having a high-voltage alternating current (AC) bus. Other embodiments of the invention relate to a vehicle having an alternator and a high-voltage AC bus.
Stationary high-voltage applications typically include a grounding and protection scheme. However, mobile high-voltage applications cannot rely on the same grounding and protection schemes as stationary high-voltage applications.
One scheme for a mobile high-voltage application is an open-circuit neutral-chassis connection to limit fault current. However, this scheme fails to limit voltage spikes during intermittent phase-chassis faults, which can damage equipment and lead to cascading failures.
Another scheme for a mobile high-voltage application is a short-circuit neutral-chassis connection. However, this scheme provides insignificant protection unless incorporated with a ground fault current interrupter (GFCI or GFI) device. This scheme is somewhat imprecise to implement, and can lead to either nuisance trips (affecting reliability) or imprecise thresholds (leading to potential personnel safety).